Characteristics and technical requirements of gene

Characteristics and technical requirements of mining general electrical equipment

(I) characteristics mining general electrical equipment is an electrical equipment without any explosion-proof measures, which is used in places where there is no explosive mixture of gas and coal dust under coal mines. Different from general electrical equipment, mining general electrical equipment has special requirements in insulation, creepage distance, electrical clearance, moisture-proof and dust-proof, underground operating conditions and so on. There is an obvious "KY" sign on the upper right of the nameplate. （2） Technical requirements: in addition to the electrical part, the general electrical equipment for mining mainly includes equipment shell, cable entry device, wiring terminal and interlocking mechanism. The shell of mining general electrical equipment, such as equipment corroded by organic solvents, must be made of non combustible or non combustible materials, with the exception of observation windows, transparent parts, gaskets, seals of cable entry devices and control handles on the shell. The equipment shell shall have certain mechanical strength and be able to withstand the impact test with specified low impact energy. Portable equipment shall be able to withstand the specified drop test. The shell of general electrical equipment for mining shall have a certain degree of protection, generally not lower than IP54. However, the protection grade at the air inlet and outlet of the external air-cooled motor fan shall not be lower than IP20 and IP10. For the equipment in the chamber without dripping water and dust intrusion, the protection grade of the starting resistance and rectifier unit with the maximum surface temperature lower than 200 ℃ shall not be lower than IP21. The protection grade of equipment without exposed live components, equipment cooled by external fans and rectifier for welding shall not be lower than IP43. There are also some special requirements for the surface temperature of mining general electrical equipment. Generally, the surface temperature of electrical equipment shall not exceed 85 ℃ (excluding motors and oil immersed transformers). Operating handle and hand wheel shall not be higher than 60 ℃. Only when the sample is broken and the test is made within the rod or the rib length that is not screwed in, it can be regarded as qualified. The part that can prevent human contact on the structure can not be higher than 150 ℃. The bolt diameter of all fasteners of mine general electrical equipment shell shall not be less than M6. The fastening bolts of the cover that is often opened shall be equipped with a device to prevent falling off. Locking devices such as spring washers shall be added to the fastening bolts. The cable entry device on the equipment shell must be able to prevent the cable from twisting, pulling off and damage. There should be a certain space inside the equipment to ensure that the cable sheath reaches a certain length (8mm). The cable entry shall be sealed with rubber or other sealing materials to prevent dust or water from penetrating into the shell from the cable entry and ensure that the shell reaches a certain degree of protection. The conductive parts of the wiring terminal introduced by the cable shall be made of copper or brass to ensure good conductivity. The wiring terminal shall reliably connect the core wire with or without lugs. The electrical clearance and creepage distance between the wiring terminals and between the wiring terminals and the ground of general electrical equipment for mining should meet the requirements. For terminals with voltage higher than 127V, aging flammable phenolic plastic cannot be used as insulation. The shell of mining general electrical equipment must have grounding bolts. For portable and mobile electrical equipment, external grounding bolts may not be set, but grounding core cables must be used. The grounding bolt shall be made of stainless steel. The project site has been preliminarily selected or plated for rust prevention. The grounding terminal can reduce the cost. It should have a certain mechanical strength and ensure reliable connection. Even if it is affected by temperature changes, vibration, etc., it cannot have bad contact. Each grounding terminal can only be connected with the grounding core of one power cable or the grounding core of two control cables. The grounding terminals of plastic shell and plastic and metal combined shell shall be connected with wires with a sectional area of more than 6mm2. In order to ensure the safe operation of electrical equipment and prevent misoperation, all switch handles of general mining electrical equipment must be self-locking after cutting off the power supply. For equipment with DC voltage higher than 60V and AC voltage higher than 36V, devices to prevent live cover opening shall be set. If such a device cannot be set, a warning sign of "power off and cover opening" shall be set. For the equipment with the above voltage levels, when the live parts may be touched after the cover is opened or the parts and components of the equipment are removed, a protective cover with a protection grade of not less than IP20 and a warning sign of "Beware of electric shock" shall be set. General electrical equipment for mining shall have moisture resistance performance and shall be subject to damp heat test as required. In order to maintain good conductivity, the bus of the equipment, the control circuit and auxiliary circuit conductors of the equipment shall be made of copper. Mining general electrical equipment mainly includes oil immersed transformers, high and low voltage switchgear and control equipment, plug-in devices, etc. In addition to meeting the requirements of mining general electrical equipment, they should also meet some special technical requirements. The special requirements for oil immersed transformers are mainly that the protection grade of the shell should reach IP44, and at the same time, there should be an oil pointer on the oil tank of the transformer to show the oil level in the shell. In any case, the oil level must be more than 10mm higher than the exposed live parts in the shell to ensure the safe operation of the transformer. The plug used to drain the oil at the lower part of the oil tank should adopt a special structure, so that it can be opened only with special tools, so as to prevent the loss of oil in the shell from being opened at will. The special requirements for high-voltage switches are: in order to ensure the safety and reliability of high-voltage switches, high-voltage switchgear should be equipped with selective leakage detection protection, short circuit and undervoltage protection. As a high-voltage motor, the high-voltage control equipment of transformer should be equipped with short-circuit, overload and undervoltage protection, and leakage locking and remote control devices can also be set. Low voltage switchgear shall also be equipped with leakage detection protection, short circuit and undervoltage protection. For low-voltage switchgear using automatic reclosing, leakage locking protection devices shall also be provided, and double sets of protection devices shall be configured for standby. When one set of protection device fails, the other set can be put into normal operation to ensure the safe use of low-voltage switch. Similarly, the low-voltage control equipment should also be equipped with short-circuit, overload, single-phase open circuit and leakage protection devices. Leakage locking and remote control devices can also be set to improve the safety and reliability of the low-voltage control equipment. If the high and low voltage switchgear and control equipment are controlled remotely, the rated voltage of its control circuit shall not be higher than 36V